To determine whether risedronate is efficacious in reducing vertebral deformity incidnece (and rate) in osteoporosis postmenopausal women. To determine whether risedronate is efficacious in reducing all osteoporosis-related fracture incidence (and rate). To determine whether risedronate is associated with an increase in spine, proximal femur, and distal radius BMD during the study in osteoporotic postmenopausal women. (deletion of effect on health-related quality of life independent from its effect on fractures, and of effect on osteoporosis-related fractures on health-related quality of life per amendment III, August 95) To determine the influence of osteoporis-related fractures on health care services utilization and costs. To determine whether risedronate treatment reduces the general osteoporosis-related health care costs of osteoporotic postmenopausal women. To determine whether risedronate treatment is safe by monitoring the adverse events, hematological, hepatic, renal, and bone safety profiles; the latter will include cortical bone mass (midshaft radius and femoral neck), and histology/histomorphometry. Incidence refers to analysis at the patient level (expressed as the proportion of patients with at least one new fracture); rate refers to the anatomical site level (Count all fractures and express as number of fractures per 1,000 patient years) See Section XI for definition of new vertebral deformity.